2181399 has 8 divisors (see below), whose sum is σ = 3172992. Its totient is φ = 1322040.

The previous prime is 2181379. The next prime is 2181419. The reversal of 2181399 is 9931812.

It is an interprime number because it is at equal distance from previous prime (2181379) and next prime (2181419).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2181399 - 2⁷ = 2181271 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 66103 = 2181399 / (2 + 1 + 8 + 1 + 3 + 9 + 9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2181329) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33019 + ... + 33084.

It is an arithmetic number, because the mean of its divisors is an integer number (396624).

2^2181399 is an apocalyptic number.

2181399 is a deficient number, since it is larger than the sum of its proper divisors (991593).

2181399 is a wasteful number, since it uses less digits than its factorization.

2181399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66117.

The product of its digits is 3888, while the sum is 33.

The square root of 2181399 is about 1476.9559912198. The cubic root of 2181399 is about 129.6915567222.

It can be divided in two parts, 21813 and 99, that added together give a palindrome (21912).

The spelling of 2181399 in words is "two million, one hundred eighty-one thousand, three hundred ninety-nine".